Piston



F. FRELIN PISTON Filed Nov. 10, 1951 INVENTOR.

HI5'ATTORNEY.

Patented Jan. 23, 1934 UNITED STATES PATENT OFFICE PISTON Application November 10, 1931 Serial N0. 574,095

1 Claim.

This invention relates to pistons, auf; more particularly to pistons for internal combustion engines and the like.

One object of the invention is to assure a firm 5 connection between the component parts of a piston.

Another object is to maintain the weight o! a piston to a minimum and a.t the same time eliminate the chances of excessive wear such as may be caused by the action of the sealing or piston rings.

Other objects will be in part obvious and in part pointed out herzeinafter.

The figure in the accompanying drawing forming a part of this specification is a sectional elevation of a piston constructed in accordance with the practice of the invention and showing the piston arranged within a. cylinder.

Referring more particulariy to the drawing,

A represents a eylinder and B a. head therefor which may be secured to the cylinder in any suitable or well known manner. The cylinder A may be provided with a suitable space or chamber C for cooling water and is bored to form a.

piston chamber D for the reception cf a. piston E having a connecting rod F which may be connected to the piston E by the usual wrist pin G.

In accordance with the practice 0f the invention the piston E is constructed of light-weight metal, such as aluminum, and has a. pair of intemal bosses H which are provided with suitable apertures J for the reception of the ends cf the wrist pin G.

The piston E is provided with an end all K having an aperture L therein which may be normally closed by a plate 0 secured to the wal1 K as by means of screws 01' bolts P 120 prevent the passage of oi1 va.pors through the aperture L. On the unter surface of the wall K and forming an integral part thereof is a. longitudinally extending annular flange or ring-like extension Q having external threads R of the square type for engagement with similar threads S in the intzrior of a head T which is threaded on the extension Q. The head T preferabiy consists of steel, iron or similar metal having a compantive1y 1ow coefiicient 0f expansion and the threads thereon are preferably a shrinkage fit on the threads 01 the extension Q.

In order to prevent the direct transmission of the heat of combustion 130 the piston E o1, more particularly, to the extension Q, the skirt T of the hea.d T is of somewhat greater length than the extension Q, thus assuring a. considerable space between the end of the extension Q and the end wa1l of the head T. As will be readily apparent, by reason cf this construction the heat absorbed by the end wall of the head T must travel tb the peripheral surface 015 the head T and along a considerable portion of the skirt T 50 before any of it; will be transmitted to the extension Q. The interior of the piston E will, in

- consequence, remain comparatively cool so that any oil contacting therewith will not be reduced to a state of extreme fluidity, nor will the interior of the piston E become coated with burnt 1ubr1- cacing oil.

Additional means may be provided to assure the retention of the head T on the cylinder E. The means illustrated for this purpose consist of a screw U threaded into the cylinder E and the head T to partly engage both.

In the periphery of the head T are a series of grooves V for the accommodation 015 sealing o1 piston rings W of a.ny well known type. In practice a piston constructed in accordance with the invention has been found to be highly efficient. The weight of the entire 'piston may be considerably reduced and at the same time the piston has the advantage of being capable of fully withstanding the wear to which it is subjected by action of the piston rings.

Another extremely desirable advantage of the present invention is that, owing to the use cf square threads as a means for connecting the piston to the head T and shrinking these elements together, a tight connection will at all times be assured between the piston and the head. This is due to the fact that the threads forming the connection between the pistonand the head will expand uniformly in all directions.

I claim:v

A piston having an end wall and an aperture in the end wall, a ring-like reduced extension on the end wa1l, a. head threaded on the extension and forming a closure for the outer end of the extension, a skirt on the hea.d and being of greater length than the extension to avoid contact between the extension and the end of the head, a. cover within the piston seated on the end wall to form a closure for the interiors of the extension and the head, and means for securing the cover to the end wall.

FRITJOF FRELIN. 

